The present invention relates generally to an electric distribution system, and more particularly, to an electric distribution system suitable for automotive applications.
Currently, the automotive industry is preparing to convert from a 14 volt electrical system to 42 volts to facilitate the increasing demand for electrical power. Various manufacturers of electrical components have and are currently designing 42 volt systems.
Integrated starter/motors or integrated starter/generators are also being proposed for automotive vehicles. Current plans employ the 42 volt system for the operation of the integrated starter/generators. However, during start up motoring, low voltage and high currents can occur. The low voltage and high current may change the performance and decrease the life of electrical components within the electrical system. Components that may be adversely affected may have to be designed to be more robust. This may increase the cost of the system and the vehicle.
It would therefore be desirable to provide an electrical architecture suitable for powering an integrated starter/generator while still allowing the system to utilize current 42 volt components.
The present invention provides an improved electrical system suitable for use in a hybrid electric vehicle.
In one aspect of the invention, an electrical system for an automotive vehicle has a first power source with a first positive terminal and first negative terminal. A second power source having a second positive terminal and a second negative terminal is also provided. A common electrical node N2 is coupled to the first negative terminal and the second positive terminal. A first load is coupled between the first positive terminal and the second node N2. A DC-to-DC converter is coupled to the first power source, the second power source and the common node.
In a further aspect of the invention, a method for operating an electrical system for an automotive vehicle comprises operating a first load with a first power source, operating a second load with a second power source, forming a series combination of said first power source and said second power source, operating an inverter with said series combination, coupling a DC-to-DC converter to the first power source and the second power source, and transferring energy from the first power source to the second power source.
One advantage of the invention is that during cold operating conditions current draw on the system will not be as great as in a single power source system.
Other advantages and features of the present invention will become apparent when viewed in light of the detailed description of the preferred embodiment when taken in conjunction with the attached drawings and appended claims.